>What about loops in the network? If someone "beyond" PSUVM sends mail >to CEARN (for example) it is easily possible that the file would go >through the BITNET-EARNET link on the way to Europe but that a reply >would come back through DEARN-GWUVM instead. If the networking software >were expecting all files from a node to come a certain direction, all >such loops would have to be eliminated and routing would have to stay >static. I'd think that it should be possible to teach it that some set of nodes have multiple paths to <reach/be reached by> them. I don't see this as a major problem (assuming that you know the entire network topology, which may not be reasonable). -njg